1. Field of the Invention
The present invention relates to a check valve. More particularly, it relates to a check valve having a sealing member connected to a dual-hinged armature.
2. Description of Related Art
Check valves are used to restrict fluid flow (e.g. a liquid or a gas) to only one direction. Selection of an appropriate check valve depends on the working fluid, its physical and chemical characteristics, the piping system, and the operating temperature and pressure as known in the art.
In one type of check valve particularly suitable for water systems, for example water filtration applications, the valve has a valve body with an inlet port and an outlet port, and a sealing member within the valve body that is biased in a normally-closed position to seal the inlet port. U.S. Pat. No. 6,247,489 discloses such a valve, and is incorporated herein by reference. As shown in the ""489 patent, the sealing member (flapper 40 in ""489) is hinged from the inner surface of the valve cover member, and biased by a spring force against the valve seat surrounding the inlet port to form a seal. This is referred to as the seated or sealed position of the sealing member.
The check valve is installed in a piping system with the inlet port connected to the upstream part of the system, and the outlet port to the downstream part. When the upstream pressure exceeds the downstream pressure, as in normal operation, the upstream fluid pressure is sufficient to overcome the biasing spring force and displace the sealing member (or flapper) from its seated position allowing fluid to enter the valve body. The fluid then exits the valve body through the outlet port unobstructed. Thus, the check valve permits fluid flow in the direction from upstream to downstream (inlet port to outlet port) during ordinary operation; i.e. when upstream pressure exceeds downstream pressure.
However, when the downstream pressure meets or exceeds the upstream pressure, which can occur, e.g., due to an obstruction downstream, the biasing spring force and/or the downstream pressure force the sealing member back into its seated position to prevent back-flow of the fluid.
The above check valve suffers from the drawback that an effective fluid tight seal is often not achieved between the sealing member and the valve seat. This is in part because the sealing member often is not squarely or snugly seated against the valve seat about its entire perimeter. As shown in FIG. 3 of ""489, the sealing member is constrained to travel in an arc (shown at C), being hinged from the cover member. Thus, the valve seat must be perfectly aligned with this arc in order to ensure an effective fluid tight seal around the entire perimeter of the valve seat. Unfortunately, such perfect alignment is often not achieved and the result is imperfect seating of the sealing member which leads to an ineffective fluid seal.
In addition, effective sealing is also hampered by the fact that the valve seat often is not very smooth. Smooth surfaces, highly desirable for effective sealing, are difficult to achieve in a cost-effective manner for the inner wall surface of a round valve body. Round valve bodies are preferred due to their fluid dynamic properties, pressure strength and other reasons.
Thus, even when the check valve is closed, an undesirable amount of fluid often can leak past the sealing member and out the inlet port into the piping system upstream of the check valve.
Accordingly, there is a need in the art for a check valve of the type described above, but which overcomes the mentioned drawbacks and effectively reduces or substantially eliminates undesirable back-flow of fluid when the sealing member is in the seated position.
A check valve is provided having a valve body and a sealing assembly provided within the valve body. The valve body has an inner wall surface, an inlet port, an outlet port and a valve seat adjacent or surrounding the inlet port. The sealing assembly comprising an armature having a proximal end and a distal end, and a sealing member pivotally attached to the distal end of the armature at a seal pivot joint. The proximal end of the armature is pivotally attached to the inner wall surface of the valve body at at least one wall pivot joint. The sealing member is biased, via a biasing force, in a seated position against the valve seat.
Another check valve is also provided. The check valve has a valve body and a sealing assembly within the valve body. The valve body has an inner wall surface, an inlet port, an outlet port and a valve seat adjacent or surrounding the inlet port. The sealing assembly comprises an armature having a proximal end and a distal end, and a sealing member pivotally attached to the distal end of the armature at a seal pivot joint, wherein the sealing member is rotatable about a first rotational axis through the seal pivot joint. The proximal end of the armature is pivotally attached to the inner wall surface of the valve body at at least one wall pivot joint such that the sealing member is translatable along an arcuate path that is substantially aligned with the valve seat. The sealing member is biased, via a biasing force, in a seated position against the valve seat.
Another valve is provided having housing that defines an interior volume and which has at least two flow ports therethrough, and a cover having a sealing assembly pivotally attached thereto. The cover is removably attachable to the housing in a plurality of orientations to selectively orient the sealing assembly adjacent any one of the ports in the housing such that fluid is permitted to flow into the interior volume of the housing through the adjacent port. The sealing assembly prevents fluid from flowing out of the interior volume through the adjacent port. The sealing assembly has an armature pivotally attached to the cover, a biasing member between the cover and the armature, a seal pivot joint, and a sealing member pivotally attached to the diverter at the seal pivot joint. The sealing member has at least one lip that extends around a perimeter of the sealing member and is supported thereby to contact the housing.